1. Technical Field of the Invention
The present invention relates to a cooling apparatus of an electronic device such as a personal computer, and particularly to a configuration of a cooling apparatus of a type which allows refrigerant liquid to circulate in a cooling system by using a pump.
2. Description of the Related Art
In recent years, high-performance semiconductor integrated circuits such as CPUs of personal computers are mounted in electronic devices. High speed and high integration of the semiconductor integrated circuits has been rapidly advanced along with demands for high-performance electronic devices, and the heating value thereof has increased as compared to that of the conventional circuits. When the heating value of the semiconductor integrated circuits increases and rises beyond a predetermined value, it is difficult to maintain the performance of the semiconductor integrated circuits and the circuits are damaged in some cases. Therefore, cooling is necessary for preventing the temperature rise of the semiconductor integrated circuits.
In place of a conventional cooling system of an air-cooling type in which forcible ventilation to a hear sink is conducted by a fan, there has been recently developed a cooling technique of a liquid-cooling type, as a cooling technique with high cooling performance and low noise, in which refrigerant liquid is allowed to circulate in a cooling system by a pump and heat generated at a heat generating portion such as a semiconductor integrated circuit is released to the refrigerant liquid from a fin portion in the cooling system.
FIG. 6 shows a configuration example of an already-commercialized cooling apparatus for cooling a CPU of a personal computer. In FIG. 6, a cooling apparatus 10′ arranged in a personal computer 1′ as an electronic device has a configuration in which a heat generating portion cooling unit 11′ including a fin portion (not shown) is arranged in contact with a CPU (Central Processing Unit) 20′ that is a heat generating portion, refrigerant liquid (water) is supplied from a discharging port of a pump 12′ to the heat generating portion cooling unit 11′, the refrigerant liquid is allowed to flow in the fin portion in the heat generating portion cooling unit 11′, heat conducted from the CPU 20′ is released to the refrigerant liquid in the fin portion so as to prevent temperature rise of the CPU 20′, the refrigerant liquid that flows out of the heat generating portion cooling unit 11′ is temporarily stored in a tank 13′ and then is cooled by a radiator (refrigerant cooling portion) 14′, and the cooled refrigerant liquid is supplied to a sucking port of the pump 12′. Piping members connect between the discharging port of the pump 12′ and an inflow port of the heat generating portion cooling unit 11′, between an outflow port of the heat generating portion cooling unit 11′ and an inflow port of the tank 13′, between an outflow port of the tank 13′ and an inflow port of the radiator (refrigerant cooling portion) 14′ and between an outflow port of the radiator (refrigerant cooling portion) 14′ and the sucking port of the pump 12′.
Among patent documents, JP-A-2007-142068 and JP-A-2006-100692 describe techniques that are conventional techniques relating to the present invention. JP-A-2007-142068 describes a configuration in which in order to improve the cooling performance with less flowing amount of refrigerant liquid and to easily comply with downsizing with a simple structure as a heat receiving portion of a cooling apparatus, a pump is integrally configured with a fin portion in a casing, refrigerant liquid sucked in the casing is allowed to pass through the fin portion, and then is allowed to flow out to the outside of the casing through an impeller of the pump. JP-A-2006-100692 describes a configuration in which in a cooling apparatus where a pump, a reserve tank, and a radiator are sequentially piled up on a heat receiving portion, a bypass flow channel is provided at the reserve tank and the arrangement of pipes is simplified in order to downsize the apparatus and minimize the reduction of refrigerant liquid.